Rockbridge County was named for Natural Bridge, an exceptional rock formation located in the county. The county was formed from Augusta and Botetourt counties in 1778, and another part of Botetourt was added later.

On March 20, 1924, Virginia passed the Racial Integrity Act that recognized only two races, white and colored. The act required that a racial description of every person be recorded at birth, and made marriage between white persons and non-white persons a felony. The law was the most famous ban on miscegenation in the United States, and was overturned by the United States Supreme Court in 1967, in Loving vs. Virginia. The registrar of Virginia's Bureau of Vital of Statistics, Dr. Walter Ashby Plecker, developed the racial criteria behind the act and adhered strictly to the one-drop rule, a historical colloquial term that holds that a person with any trace of African ancestry is considered black. The Racial Integrity Act was subject to the Pocahontas exception. Since many influential families claimed descent from Pocahontas, the legislature declared that a person could be considered white with as much as one-sixteenth Indian ancestry. This law, along with the Sterilization Act also of 1924, imposed the practice of scientific eugenics in the Commonwealth.